An independent inquiry is to be carried out into the accuracy of election polls after underestimates of the Conservatives' lead over Labour.

Predictions of a neck-and-neck race, a near-balanced parliament, and a potential constitutional crisis following the General Election put forward by all major pollsters during the campaign were proved drastically wrong.

In the end, David Cameron's party secured an overall majority, something even the exit poll of 22,000 voters at 141 polling stations did not detect.

The British Polling Council (BPC), which acts as the association for opinion pollsters, will look into the causes of the "apparent bias" and make recommendations for future polls.

Chancellor George Osborne said the pollsters would have "a big post-mortem" while Michelle Harrison, a pollster at TNS, said it had been a "mixed night for the polling community".

Ms Harrison told Sky News: "The distribution of the seats may not be our greatest moment but in other areas I think we have done quite a good job.

"In general it's a mixed night for polling community.

"If we look at the really big trends of the night - the fact the Scottish nationalists have eaten Labour alive in Scotland, we saw it coming. I don't think even in our wildest dreams we expected it to be quite so momentous."

The BPC, which counts all major UK pollsters among its members, said in a statement: "The final opinion polls before the election were clearly not as accurate as we would like, and the fact that all the pollsters underestimated the Conservative lead over Labour suggests that the methods that were used should be subject to careful, independent investigation.

"The British Polling Council, supported by the Market Research Society, is therefore setting up an independent inquiry to look into the possible causes of this apparent bias, and to make recommendations for future polling.

Survation said it conducted a telephone poll on Wednesday evening which showed the Tories on 37% and Labour on 31% but "chickened out" of publishing it as it appeared so out of line with other surveys.

Its chief executive Damian Lyons said he would "always regret" the decision but would not be carrying out an internal review of his methodology.

Meanwhile, ICM director Martin Boon appeared to sum up the mood among Britain's pollsters, tweeting "oh s**t" after the publication of the exit poll showing the Tories would be by far the largest party.